Ultrafast discharge properties and enhanced energy density in lead‐free NaNbO₃‐based relaxor ferroelectric ceramics

Abstract

NaNbO₃‐based (NN) energy storage ceramics are known for exhibiting high maximum polarization (P_max) and large recoverable energy density (W_rec). However, the huge energy loss density (W_loss) has been a limiting factor in improving energy storage performance. Therefore, a ternary system was designed to achieve both huge W_rec and efficiency (η). The combination of 0.35Bi(Zn_0.5Ti_0.5)O₃–0.65BaTiO₃ (BZTBT) was chosen to reduce grain size and disrupt the long‐range ordered domains, thereby inducing the polar‐nano‐regions to mitigate W_loss. The optimal performance was achieved with the 0.75NaNbO₃–0.25(0.35Bi(Zn_0.5Ti_0.5)O₃–0.65BaTiO₃) (0.75NN–0.25BZTBT) ceramic, which exhibited a high W_rec = 2.68 J/cm³ and superior η = 82.7% under 310 kV/cm. Remarkably, the 0.75NN–0.25BZTBT ceramic displayed an exceptionally fast discharge time to 90%, t_0.9 = 88 ns, coupled with a huge energy density W_d = 0.95 J/cm³. This study demonstrates the significant potential of 0.75NN–0.25BZTBT ceramic in the realm of energy storage and rapid charge–discharge applications.